1. Field of Invention
The present invention relates to a machine for skinning fish or fish fillets, comprising a skinning roller, a skinning knife, a cutting edge on said skinning knife being formed by two faces of said skinning knife including an acute angle therebetween, one of said two faces being provided to press the skin of fish or fish fillets against said skinning roller while the other face forms a back face.
2. Description of Prior Art
Such skinning machines developed from known bacon slicers are noted for their simple construction and their quietness, and have been, therefore, in demand by people working in the fish processing industry. A fundamental obstacle to the possibility of being able to skin fish or fish fillets of different kinds of fish and of different fish sizes with skinning machines of this or similar structure lies in that a secure conveying of the skin between the presser face and the surface of the skinning roller is not achievable, and, therefore, several of the fish fillets run over the skinning knife unskinned. The application of these machines is therefore limited to the peeling off of the skin of whole soles.
It is known from British Patent No. 1 491 609 to use a knife, which has in the immediate vicinity of its cutting edge a projecting wall portion, which extends transversely to the conveying direction of the fillet portions and away from that side of the skinning knife turned towards the roller. Thus, a certain resistance is intended to be applied against the incoming fillet portion and the front part of the fillet portion to be forced against the cutting edge, whereby this operatively and securely should cut in between the external surface layer and the fillet portion. It remains to be seen, if and how far these goals are achieved; it has been shown that skinning machines fitted out with knives of this kind are not in the position to achieve a secure skinning of fish fillets of a broad variety of fish, because a quantity of these fillets run unskinned over the so-called "knife". Due to the non-availability of a cutting edge built by surfaces lying at an acute angle to each other, a skinning machine fitted with a "knife" of this kind is completely unsuitable for the skinning of fillets of plaice or similar flat fish. Further, in view of the undesired strain on tender fillets by the high projecting "knife", a skinning machine fitted with a knife of this type is also unsuitable for the skinning of small or soft fish fillets, because as a consequence of the lacking of a suitable cutting edge, these fillets are pulled by the roller, before completion of the skinning process, between the presser face and the surface of the roller, reduced to shreds by the teeth of the latter, and thereby are destroyed.